Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wilder weather exerts a stronger influence on biodiversity than steadily changing conditions

18.01.2010
An increase in the variability of local conditions could do more to harm biodiversity than slower shifts in climate, a new study has found.

Climate scientists predict more frequent storms, droughts, floods and heat waves as the Earth warms. Although extreme weather would seem to challenge ecosystems, the effect of fluctuating conditions on biodiversity actually could go either way. Species able to tolerate only a narrow range of temperatures, for example, may be eliminated, but instability in the environment can also prevent dominant species from squeezing out competitors.

"Imagine species that have different optimal temperatures for growth. In a fluctuating world, neither can get the upper hand and the two coexist," said Jonathan Shurin, an ecologist at the University of California, San Diego who led the project. Ecologists have observed similar positive effects on populations of organisms as different as herbacious plants, desert rodents, and microscopic animals called zooplankton.

Now a study of zooplankton found in dozens of freshwater lakes over decades of time has revealed both effects. Shurin and colleagues found fewer species in lakes with the most variable water chemistry. But lakes with the greatest temperature variations harbored a greater variety of zooplankton, they report in the journal Ecology Letters January 21.

Their study considered data from nine separate long-term ecological studies that included a total of 53 lakes in North America and Europe. In addition to sampling zooplankton, scientists had also taken physical measurements repeatedly each season for periods ranging from 3 to 44 years.

From these data, they calculated the variability of 10 physical properties, including pH and the levels of nutrients such as organic carbon, phosphorous and nitrogen. Temperatures and the amount of oxygen dissolved in the water at both the surface and bottom of each lake were also included. The authors also teased apart variation based on the pace of change with year-to-year changes considered separately from changes that occurred from season-to-season or on more rapid timescales.

Zooplankton populations respond quickly to changes because they reproduces so fast. "In a summer, you're sampling dozens of generations," Shurin said. "For mammals or annual plants, you would have to watch for hundreds or thousands of years to see the same population turnover."

At every time scale the pattern held: Ecologists found fewer species of zooplankton in lakes with fluctuating water chemistry and greater numbers of species in those with varying temperatures. The authors noted that the temperature variations they observed remained within normal ranges for these lakes. But some chemical measures, particularly pH and levels of phosphorous, strayed beyond normal limits due to pollution and acid rain.

Environmental variability through time could either promote or reduce biodiversity depending on the pace and range of fluctuations, the authors suggested.

"It may depend on the predictability of the environment. If you have a lot of violent changes through time, species may not be able to program their life cycles to be active when conditions are right. They need the ability to read the cues, to hatch out at the right time," Shurin said. "If the environment is very unpredictable, that may be bad for diversity, because many species just won't be able to match their lifecycles to that."

Shurin's 10 co-authors include scientists from environmental agencies in Canada, and universities and research institutes in Canada, Germany, Switzerland and the United States. The Natural Sciences and Engineering Research Council of Canada supported Shurin's work on this study.

Jonathan Shurin | EurekAlert!
Further information:
http://www.ucsd.edu

More articles from Ecology, The Environment and Conservation:

nachricht Safeguarding sustainability through forest certification mapping
27.06.2017 | International Institute for Applied Systems Analysis (IIASA)

nachricht Dune ecosystem modelling
26.06.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Touch Displays WAY-AX and WAY-DX by WayCon

27.06.2017 | Power and Electrical Engineering

Drones that drive

27.06.2017 | Information Technology

Ultra-compact phase modulators based on graphene plasmons

27.06.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>